Purpura fulminans is an acute, rapidly progressive hemorrhagic necrosis of the skin attributable to dermal vascular necrosis that is associated with disseminated intravascular coagulation. It is a rare and occasionally life-threatening disorder that occurs most commonly in the setting of acute, severe bacterial or viral infection, or as a postinfectious syndrome after infections such as primary varicella or scarlet fever.^1-4 Postinfectious purpura fulminans usually occurs 7 to 10 days after onset of symptoms of the acute infection.⁵ The ecchymotic lesions are most commonly distributed symmetrically on the lower extremities and buttocks, although the trunk and upper extremities can be involved. Visceral involvement is less frequent but can lead to hematuria or gastrointestinal hemorrhage.⁶

Transient or congenital deficiencies of protein C or protein S have been documented in many cases of purpura fulminans in recent years.^1,4,7,8 Protein C is the best known among the identified anticoagulant factors in the delicate molecular balance of hemostasis. Activated protein C degrades activated coagulation factors VIIIa and Va, attenuating their procoagulant activation of factors X and prothrombin. Protein S is a cofactor to activated protein C, which accounts for the increased risk of thrombosis associated with protein S deficiency states.⁹

Factor V Leiden, a factor V variant resulting from a single point mutation at nucleotide 1691 (guanine to adenine, resulting in arginine 506 to glutamine), has been recognized recently as a risk factor for thrombotic events in adults.¹⁰ Reported thromboses in children with factor V Leiden have included catheter-related thrombosis¹¹ and renal vein and venous sinus thrombosis in a neonate.¹² The presence of factor V Leiden also heightens the risk for thrombotic events among adolescents and young women who use oral contraceptives (odds ratio, 4.9; 95% confidence interval, 2.0-11.7).¹³

The factor V Leiden mutation confers resistance to protein C activation and the subsequent degradation of factors Va and VIIIa. . . . [Full Text of this Article]